I've only journaled in the context of prayer, for which it's been incredibly helpful, especially to look back on old prayer journals years later.

But as to journaling in general, plenty of famous men throughout history have, so it seems more to be a general human thing. A theory I happened across somewhere posited social media had taken the place of journaling via 'scratching the itch' that journaling is designed for. Which might have something to do with journaling falling out of widespread use.